Today's Los Angeles Times has an article about a North Hollywood junkyard that stocks a huge quantity of used aerospace parts, from valves to rocket engines. Norton Sales Inc. got started in the early 1960s. The junkyard had fallen on hard times, with the collapse of the Los Angeles-area aerospace economy in the 1980s, but it's making something of a comeback now with NASA's new plans for moon and Mars missions. The customers used to be rich Hollywood types; nowadays they are as likely to be private space entrepreneurs. "It's dangerous coming to a place like this," said Dave Masten of Masten Space. "It's like shopping on an empty stomach."